The present invention relates to minimum invasive balloon catheters for non-continuous lesions on body tissues, and in particular, on sphincter tissues of body lumen.
In the past, heat induced lesions around a body lumen has been used to shrink the body lumen to treat incontinence. And discontinuous lesions evenly distributed around a body lumen circumference was made to have some viable tissues left between ablated tissues to maintain some elasticity for opening and close, while the overall lumen section was contracted after ablation.
Radio frequency (RF) ablation catheters has been used to ablate sphincter tissues in body lumen, to treat deceases such as gastro esophageal reflux, fecal incontinence and urinary stress incontinence. Although RF catheters can generate sufficient heat to cause sphincter tissue to shrink, there are three drawbacks of RF ablation to shrink a body lumen. The first is that it often results in tissue charring because RF electrode edges have high current density and generate much higher heat than non-edged areas of the electrode. So RF electrodes have to be cooled by a fluid during ablation. The second is that needle electrodes had to be used to make discontinuous lesions and minimize mucosa damage. The risk of the needles is that it can perforate a body lumen. The third is that the needle electrodes could not make many lesions at once.
Balloon catheters filled with fluid heated electrically were used to ablate uterus. And balloon catheters heated by ultrasound transducer were used to ablate cardiac tissue. These balloon catheters have advantages of evenly heating around balloon surface without tissue charring, and good tissue contact in body lumen, and ablating large areas at the same time. Yet these balloon catheters have not been used to shrink body lumen by ablating sphincter tissue. One of the reasons for that could be due to the fact that the balloon catheters in the prior arts tend to make continuous lesions especially circumferencely around a body lumen, which is not desired.
Objectives of this invention are to make balloon ablation catheters which can make non-continuous multiple lesions over large areas of body lumen for tightening.
The balloon catheters according to the present invention have surface contours with protrusions and grooves to make non-continuous lesions. There is a heating element inside the balloon. The balloon will be filled with a fluid before ablation to expand the balloon for tissue contact in a body lumen, and to transfer heating energy from the heating element to the tissue in contact with the balloon. Since the balloon surface has contours with grooves and protrusions, the tissue contact will not be continuous along the balloon surfaces, and therefore the ablation on the tissue will not be continuous.
Balloon catheters have advantages of no char and no perforation on tissues when making lesions, and many lesions made at the same time on large areas with controlled distances.